Numerical analysis of the role of p-MoSe2 interfacial layer in CZTSe thin-film solar cells using SCAPS simulation

This work aims to report on the effect of p-MoSe2 transition metal dichalcogenide as an interfacial layer between the CZTSe absorber and Mo back contact in the CZTSe solar cells, using the solar cell capacitance simulator (SCAPS-1D). The results demonstrated that the p-MoSe2 layer benefits the CZTSe/Mo heterojunction by mediating the favourable quasi-ohmic contact to the CZTSe solar cell, which is revealed by a higher J–V characteristic slope and conversion efficiency improved from 16.17% to 25.19%. Various performance parameters such as open-circuit voltage (Voc), short circuit current (Jsc), fill factor (FF), and power efficiency (η) at a wide range of different layer parameters like thicknesses, bandgap energies, and carrier concentration (NA) were studied in detail. The results show that when the thickness of the MoSe2 interfacial layer is less than 65 nm, it causes a deterioration of overall cell performance. This is ascribed to the impedes of the drift of the photogenerated holes due to the increment of the barrier heights at the CZTSe/MoSe2 and MoSe2/Mo interfaces. Additionally, increasing the NA above 1017 cm−3 improves cell performance due to the enhanced band alignment at the back contact. The effect of the series resistance (Rs) on the CZTSe solar cell is also investigated. The obtained results show that by increasing the Rs from 1 to 5 Ω cm2, the efficiency decreases from 25.19% to 16.79% of the CZTSe solar cell using the MoSe2 layer. Finally, the impact of the device operating temperature is explored in the range from 250 K to 465 K. We noticed a drop of ~ 10% in η, from 26.80% to 15.89%, in the above range, due to the escalating reverse saturation current associated with high temperature.